13 `And thou, speak unto the sons of Israel, saying, Only, My sabbaths ye do keep, for it [is] a sign between Me and you, to your generations, to know that I, Jehovah, am sanctifying you;
13
“Say to the Israelites, ‘You must observe my Sabbaths. This will be a sign between me and you for the generations to come, so you may know that I am the LORD, who makes you holy.
Young's Literal Translation is in the public domain.